The present invention relates to data transmission via a network, and particularly to a terminal apparatus, a data transmitting apparatus, a data transmitting and receiving system, and a data transmitting and receiving method for controlling transmitted data according to capability of the terminal apparatus.
In contents distribution by video-on-demand service, distribution of live video, or real-time communication such as videoconferencing, the videophone and the like, a system is devised which transmits data appropriate for capacity of terminal apparatus having different performances which data is obtained from the same source data to the terminal apparatus, using a layered coding (scalable coding) technique.
Conventionally, a server apparatus or the like on a data transmitting side is required to prepare a data file in a different format according to capability of a terminal apparatus to which to transmit data or prepare a different data file according to a transmission rate.
However, the use of the layered coding technique enables data from a single data file to be distributed simultaneously to terminal apparatus having different performances, for example a terminal apparatus having a display with a low resolution and a CPU (Central Processing Unit) with a low processing capability, such as a portable telephone or the like, and a terminal apparatus having a monitor with a high resolution and a CPU with a high processing capability, such as a desktop personal computer or the like.
For such data transmission according to the capability of the terminal apparatus, information indicating the capability of the terminal apparatus needs to be notified in advance to a server apparatus or the like serving as a data transmitting apparatus, and a complicated negotiation or the like is required between the terminal apparatus and the server apparatus.
In the case of a terminal apparatus such as a PC (Personal Computer) having various advanced functions and including an OS (Operating System) with a high processing capability, for example, it is easy to implement a protocol for notifying the information indicating the capability of the terminal apparatus and performing the negotiation with the server apparatus as described above.
Recently, however, an IP (Internet Protocol) address is given even to a portable telephone whose data processing capability is not very high and whose memory included therein is limited in capacity and the like and to a household electrical appliance that does not include even an OS. It is very difficult for the household electrical appliance and the portable telephone having a network connecting function but a relatively low data processing capability to implement an advanced protocol as in the case of the PC to perform a negotiation in communication.
Hence, data appropriate for the capability of the terminal apparatus having a network connecting function but a relatively low data processing capability cannot be delivered to the terminal apparatus.